Seems logical to me- Rig the electronics a bit differently so that a special cable not only carries your signal, but also the means to switch on 1,2,3, or any combination of your PU's, down to some type of foot controller.
A friend of mine did that once, using a special 3 pole cable (looked pretty much like an XLR cable but with an extra pole, might've even been a 5 pole cable, don't remember anymore).
He even had his guitar switching controlled by one of the switching systems back then (maybe from EXEF, now kinda extinct german company, again I don't exactly remember).
Certainly made everyone go like "wow, now your hands can concentrate on playing only" or so.
But that didn't last long, as it turned out to be the least practicable thing ever. Sure, he kept the original switching intact (no problem, you can simply tap each pickup wire) so he could still use it as a normal guitar - but all that external switching never paid off. I mean, one of the most common things ever has got to be switching from, say, neck to bridge PU during a solo spot to help "intensify" things. With that external switching, not only would you have to be close to your pedalboard all the time, no, you'd also have to program a separate patch for each PU position.
Alternatively, you could of course as well not make the external switching programmable. But what about when you need to switch patches and pickups? Double feet action - whereas my hand would just flick the PU switch while stepping on the buttons responsible for the patches.
The only thing I really liked was when he built the thing back. As he had all that stuff intact already, he came up with some switching that would route the pickups through different signal paths. When he showed that to me, neck and bridge were even running through entirely separated systems - and I gotta say that playing through that setup was quite impressive. But it probably wouldn't have made *that* much of a difference if it was only one plain guitar signal being split. Part of the sensation very likely has been that back then you didn't have an option to easily split your signal and amplify each side separately - which is a piece of cake today (and not even remotely expensive anymore).
Anyhow, if that was such a great thing, I'm sure more folks would do it - it's not exactly much of a technical issue, especially in case you're only using a guitar with 2 pickups, in that case a bog standard XLR cable would do.